In this study, we aimed to retrospectively assess the correlation of pseudocholinesterase (PChE) levels with age, gender, body weight and diagnosed psychiatric diseases in electroconvulsive therapy (ECT) cases. Methods: This retrospective study was conducted at Bülent Ecevit University Hospital, Zonguldak, Turkey, between 2007 and 2011. In the study, 193 ECT case files were retrospectively scanned to evaluate PChE values before ECT and other file information. Results: There was no difference between gender in terms of PChE levels. Correlation analysis determined a weakly positive correlation between age (p=0.013; correlation coefficient [cc]: 0.178) and body weight (p less than 0.001; cc: 0.273) and PChE levels. No correlation was found between age, gender, weight or psychiatric diagnosis, and PChE levels. Conclusion: Neuromuscular blockage is a significant factor that increases patient safety, while increasing the efficacy of ECT. In choosing muscle relaxant agents, both patient factors and the pharmacological properties of the neuromuscular blocker should be considered. We think that in situations with delayed recovery of ECT cases without identified PChE levels, low PChE levels must be considered.